<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <script>
    // 修改数据
    // let arr = ['lll', 'kkk', 'jjj']

    // for (let i = 0; i < arr.length; i++) {
    //   arr[i] = arr[i] + '老师'
    //   document.write(arr[i] + '<br>')
    // }

    let arr = ['lll', 'kkk', 'jjj']
    arr.push('hhh')
    document.write(arr)
  </script>

</body>

</html>